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The present invention relates generally to a method and system for utilization of bioelectrical impedance analysis (BIA) in a biological model for body composition analysis (BCA) to provide an objective assessment of an organ""s and/or biological entity""s volume and distribution of fluids and tissue as well as the electrical health of cells and membranes.
More particularly, the present invention relates to a method for determining illness of a biological entity, progression to death of said biological entity, and/or timing of death of said biological entity, and also relates to a method of organ vitality assessment for transplantation of said organ being assessed.
The relevant art is exemplified by the following U.S. patents.
U.S. Pat. No. 2,111,135 issued in 1938 to Bagno entitled xe2x80x9cAPPARATUS AND METHOD FOR DETERMINING IMPEDANCE ANGLESxe2x80x9d discloses an apparatus for measuring the electrical phase displacing properties or impedance angle of humans, animals, and vital tissues. There is also disclosed a method for measuring the phase angle due to the impedance of an animal having properties of varying resistance and capacitance due to changes in muscular tension, comprising the steps of passing an alternating current through the animal, and measuring the phase during changes of resistance and capacitance, said measurement of phase being made so that the phase angle remains substantially independent of variations in the total impedance.
U.S. Pat. No. 2,852,739 issued in 1958 to Hansen entitled xe2x80x9cREMOTE CONTROLLED IMPEDANCE MEASURING CIRCUITxe2x80x9d discloses a remotely controlled measuring circuit for a monitoring apparatus of the type which provides an indication of the change in electrical impedance in a sensing element brought about by some change in the physical or chemical characteristics of an object being monitored.
U.S. Pat. No. 3,085,566 issued in 1963 to Tolles entitled xe2x80x9cAPPARATUS FOR MEASURING THE ELECTRICAL RESPONSE OF LIVING TISSUExe2x80x9d discloses an apparatus for measuring tissue resistance and capacitance independently of tissue potential. While particularly useful in measurements on living tissue, the invention may also be used to measure electrical effects as the tissue dies.
U.S. Pat. No. 3,316,896 issued in 1967 to Thomasset entitled xe2x80x9cAPPARATUS AND METHODS FOR THE MEASURE OF THE ELECTRICAL IMPEDANCE OF LIVING ORGANISMSxe2x80x9d discloses a method for simultaneously and associatively determining the individual impedances of the extracellular contents and the intracellular contents of a living organism, which consists in measuring the total impedance of the organism between two selected points thereof at predetermined frequencies.
U.S. Pat. No. 3,498,288 issued in 1970 to Max et al. entitled xe2x80x9cDEVICE FOR CORRECTING THE MEASUREMENT OF POTENTIALS DETECTED BY CONTACT ELECTRODESxe2x80x9d discloses a device for rapidly correcting the measurement, supplied by an apparatus comprising a continuously operating metering amplifier, of the potential detected in an organ of the human body by means of two contact electrodes. The device includes means for resetting the zero of the metering amplifier, and means for compensating the polarization voltage of the contact electrodes in use.
U.S. Pat. No. 3,882,851 issued in 1975 to Sigworth entitled xe2x80x9cIMPEDANCE PLETHYSMOGRAPHxe2x80x9d discloses a device provided with voltage and current electrodes with a variable current source connected to the current electrodes to send a varying current to a biological segment to provide a voltage that is used to generate a signal representing a percent of change in the resistance of the biological segment.
U.S. Pat. No. 4,823,804 issued in 1989 to Ghislaine et al. entitled xe2x80x9cAPPARATUS FOR MONITORING ACTIVITY LEVEL OF HUMAN ORGANxe2x80x9d discloses an apparatus for monitoring the motricity of an organ by a counterreaction technique known as bioretroaction. The apparatus has at least one pair of differential-connected sensors placed near the organ for obtaining differential electric input signals representing the activity of the organ. A computer processes the input signals to generate an output signal which is characteristic of the activity level of the organ.
U.S. Pat. No. 5,372,141 issued in 1994 to Gallup et al. entitled xe2x80x9cBODY COMPOSITION ANALYZERxe2x80x9d discloses a body composition analyzer which provides the resistive and reactive components of a body""s measured impedance as well as body fat information and ideal weight information.
U.S. Pat. No. 6,024,698 issued in 2000 to Brasile entitled xe2x80x9cAPPARATUS FOR MONITORING FUNCTIONAL CHARACTERISTICS OF AN ORGAN INTENDED FOR TRANSPLANTATIONSxe2x80x9d discloses a technique to prospectively determine the potential function of an organ posttransplantation by measuring functional characteristics related to organ metabolism while the organ is being perfused in an ex vivo warm preservation system at near normal rate of metabolism by measuring parameters of organ product or circulated perfusate during ex vivo preservation. Values of the measured parameters are compared to reference interval values (an established normal range) so that a value of a measured parameter outside the reference intervals may indicate organ damage, injury, or poor functional capabilities that may affect the function of the organ posttransplantation.
The desiderata of the present invention are to avoid the animadversions of conventional methods and techniques, and to provide a novel method for determining illness of a biological entity, progression to death of said biological entity, and/or timing of death of said biological entity, and to provide a novel method of organ vitality assessment for transplantation and/or xenotransplantation of said organ being assessed.
The present invention provides a method for determining illness of a biological entity, progression to death of said biological entity, and/or timing of death of said biological entity, comprising the steps of: providing normal values of resistance, reactance, phase angle, extracellular water volume, and intracellular water volume of the whole body of the biological entity; measuring initial values of resistance, reactance, phase angle, extracellular water volume, and intracellular water volume of the whole body of the biological entity; taking whole body measurements of resistance, reactance, phase angle, extracellular water volume, and intracellular water volume at predetermined intervals of time; recording said whole body measurements; comparing initial values of said whole body measurements to normal values of said whole body measurements and to serially measure values of said whole body measurements; and determining, from said comparison step, hallmarks of said illness of said biological entity, said progression to said death of said biological entity, or said death of said biological entity.
The present invention also provides a method of organ vitality assessment for transplantation of said organ being assessed, comprising the steps of: placing signal introduction electrodes on opposite lateral peripheral borders of said organ upon harvesting of said organ; placing signal detection electrodes at superior and inferior borders of said organ for a first part of an initial measurement upon said harvesting of said organ; measuring and recording first values of resistance and reactance of said organ in said initial measurement; then placing said signal introduction electrodes on said superior and said inferior borders of said organ; placing said signal detection electrodes on said opposite lateral borders of said organ; measuring and recording second values of said resistance and said reactance of said organ; and comparing said first and second values to normal values to determine if said organ is acceptable or not for said transplantation.